Evaluation And Utilization Of Salt Tolerance Of Spinach Germplasm Resources

Soil salinization is a strong obstacle to the development of agriculture in our country.The breeding strategy should been changed,from controlling crops adapted to saline-alkali land to breeding saline-alkali-tolerant plants to adapt to saline-alkali land.As a common leafy vegetable,spinach is not only rich in nutrients,but also has a fast growth rate and a short cycle.It is also one of the vegetables with strong salt and alkali tolerance.Therefore,it is of great significance to strengthen the systematic evaluation and utilization of the salt tolerance of spinach germplasm resources for the breeding of new salt-tolerant spinach varieties.In this experiment,78 core spinach germplasm resources collected and preserved by the Germplasm Resource Center of Shanghai Normal University were used as research materials.The spinach was treated with 300 mmol/L and 500 mmol/L salt stress at the germination stage and seedling stage.Respectively,the relevant germination indicators were measured at the bud stage,and the relevant external morphological and physiological indicators were determined at the seedling stage.Then a comprehensive evaluation of the salt tolerance characteristics of spinach germplasm at germination stage and seedling stage was carried out through cluster analysis,principal component factor analysis,correlation analysis and membership function value method.It provides theoretical support for the screening of salt-tolerant spinach germplasm resources and the breeding of new salt-tolerant spinach varieties.The results showed that: in the bud stage,different concentrations of salt stress treatments would affect the germination of seeds,and the higher the salt stress concentration,the greater the effect.The germination of some materials was promoted after 300 mmol/L salt stress treatment,but was inhibited of most materials.Each two indexes of germination rate,relative salt damage rate,relative root length,germination index and vigor index showed extremely significant correlation,except that germination potential was only significantly correlated with relative root length.Except for the relative salt damage rate,which had a very significant negative correlation with other indicators,all other indicators had a very significant positive correlation.The germination of spinach was inhibited under 500 mmol/L salt stress treatment.There is a very significant correlation between any two indicators in the germination potential,germination rate,relative salt damage rate,relative root length,germination index and vigor index,except for the relative salt damage rate and other indicators,which have extremely significant negative correlations.In addition,there is a very significant positive correlation between other indicators.Cluster analysis was carried out on the germination indexes of each material under different concentrations of salt stress and 7resistant materials were obtained by combining the clustering results under different concentrations,CS242-9,CS308-4,CS401-5,US112-5,US228-6,US34-3 and US44-5.Under different concentrations of salt stress,60 materials survived in the 300mmol/L treatment,and 41 materials survived in the 500 mmol/L treatment.The external morphological indicators at the seedling stage showed that the mean values of the five indicators decreased with the increase of the treatment concentration,among which the plant width and petiole length of the 500 mmol/L treatment decreased most significantly.Under 300 mmol/L salt stress,the chlorophyll content,oxalic acid content,soluble sugar content,malondialdehyde content and three enzyme activity indexes of most materials showed an upward trend,while ascorbic acid content and nitrate nitrogen content showed a downward trend.The soluble sugar content of the material did not change significantly.Under the 500mmol/L salt stress treatment,the oxalic acid content,soluble sugar content,malondialdehyde content and POD enzyme activity indexes of most materials showed an upward trend,while the ascorbic acid content,nitrate nitrogen content,CAT and SOD enzyme activities showed a downward trend.The chlorophyll content and soluble protein content of the material did not change significantly.This was different from the changes in the quality indexes of spinach materials under 300 mmol/L salt stress.10 salt-tolerant materials were obtained,US44-5,US65-3,CS304-8,US236-10,CS157-20,CS233-5,CS401-5,US112-5,US179-9and US333-6.Based on the experimental results at the bud stage and seedling stage,a total of 10 materials with strong resistance and 8 materials with non-resistance were obtained,The materials with strong resistance were: US44-5,US65-3,CS304-8,US236-10,CS157-20,CS233-5,CS401-5,US112-5,US179-9 and US333-6;non-resistance materials were: US330-16,US68-7,US76-6,US192-5,US60-5,US63-5,US70-3 and US71-2.Finally,compared with the phenotypic characters of the resistant materials and the nonresistant materials,the results can provide a reference for the subsequent cultivation of salt-tolerant high-quality spinach and a basis for the study of salt-tolerance mechanism.